JDK-8149365 : aarch64: memory copy does not prefetch on backwards copy
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: 9
  • Priority: P4
  • Status: Resolved
  • Resolution: Fixed
  • OS: linux
  • CPU: aarch64
  • Submitted: 2016-02-08
  • Updated: 2021-02-01
  • Resolved: 2016-02-09
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JDK 9 Other
9 b107Fixed openjdk8u292Fixed
Related Reports
Relates :  
JDK-8257192 - Integrate AArch64 JIT port into 8u
Description
The implementation of memory_copy_longs in aarch64 does not do prefetch on backwards copies.

This can have a significant performance impact on some micro arches.

In addition there is a feature where -XX:PrefetchCopyIntervalInBytes is ignored and always set to 256